Data transfer in memory card system

Abstract

A memory card system includes a host that issues a read command and a memory card that upon receiving the read command sends read data to the host in synchronism with a read clock signal generated within the memory card. In addition, the memory card sends the read clock signal to the host, and the host receives the read data in synchronism with the read clock signal, for increasing the allowable setup time period at the host.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]The present application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 2006-74291, filed on Aug. 7, 2006, which is incorporated herein by reference in its entirety.TECHNICAL FIELD[0002]The present invention relates generally to memory card systems, and more particularly, to increasing allowable setup time at a host by transferring read data from a memory card to a host along with a read clock signal generated at the memory card.BACKGROUND OF THE INVENTION[0003]FIG. 1 shows an example memory card system 100 of the prior art, including a memory card 102 and a host 104. The host 104 may be a portable electronic device such as a mobile phone, a MP3 player, or a PMP (portable media player). The memory card 102 may be a flash memory card as one example. The host 104 includes a host controller 106 and a host connection unit 108. The card 102 includes a card connection unit 110, a card controller 112, and a memory unit 11...

AI Technical Summary

Benefits of technology

The present invention relates to a memory card system that allows for an increased setup time period at the host when receiving read data. This is achieved by generating and transmitting a read clock signal when sending read data to the host. The host includes a flip flop that latches in the read data from the memory card clocked with the read clock signal. The memory card system also includes a host data processor and a host memory device having sequences of instructions stored thereon, which causes the host data processor to perform the steps of sending the read command to the memory card. The memory card includes a read clock signal generator that is controlled to generate the read clock signal when the memory card receives the read command. The memory card system also allows for an increased allowable setup time for receiving the read data at the host by controlling the phase relationship between the read data and the read clock signal received at the host. This eliminates an output delay from the memory card and increases the allowable setup time at the host.

Problems solved by technology

However, such allowable setup time period t5 may limit high frequency operation of the memory card system 100.

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